package kr.hkit.powerjava.chapter16;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

class MyPanel extends JPanel implements ActionListener{

	//boolean flag=false;
	private int light_number=0;
	
	public MyPanel(){
		setLayout(new BorderLayout());
		JButton b= new JButton("traffic light turn on");
		b.addActionListener(this);
		add(b, BorderLayout.SOUTH);
	}
	@Override
	protected void paintComponent(Graphics g) {
		super.paintComponent(g);
		g.setColor(Color.BLACK);
		g.drawOval(100, 100, 100, 100);
		g.drawOval(100, 200, 100, 100);
		g.drawOval(100, 300, 100, 100);
		if(light_number==0){
			g.setColor(Color.RED);
			g.fillOval(100, 100, 100, 100);
		}else if(light_number==1){
			g.setColor(Color.GREEN);
			g.fillOval(100, 200, 100, 100);
		}else{
			g.setColor(Color.YELLOW);
			g.fillOval(100, 300, 100, 100);
		}
	}
	@Override
	public void actionPerformed(ActionEvent arg0) {
		if(++light_number>=3){
			light_number=0;
			
		}repaint();
	}
}
	public class MyFrame extends JFrame{
		public MyFrame(){
			add(new MyPanel());
			setSize(300, 500);
			setVisible(true);
		}
		public static void main(String[] args) {
			new MyFrame();
		}
}
